Changes in Glucose Oxidation During Growth of Embryonic Heart Cells in Culture

Warshaw, Joseph B.; Rosenthal, Miriam D.

doi:10.1083/jcb.52.2.283

Cited by 22 publications

(9 citation statements)

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“…We have reported similar results relating to lung growth of hyperoxic animals (25). Since proliferative growth has been associated with increases in G6PDH activity (26), it would appear that in the case of growth-restricted lungs of oxygen-treated animals that the increasc in G6PDH activity may be utilized to support antioxidant systems, rather than for synthetic processes such as fat or nucleotide synthesis.…”

Section: Days Insupporting

confidence: 60%

The Responses of Glutathione and Antioxidant Enzymes to Hyperoxia in Developing Lung

et al. 1985

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ABSTRACT. Total glutathione levels and the activity of enzymes associated with antioxidant protection in neonatal lung are increased in response to hyperoxia. GIutathione levels in developing rat lung decreased from 24 nmol/mg protein on day 19 of gestation to approximately 12 nmol/ mg protein at birth. The initial decrease in glutathione may be due to emergence of other antioxidant systems. Newborn rats placed in 100% oxygen showed a rapid and sustained increase in total glutathione levels which was primarily due to an increase in reduced glutathione. Expiants obtained from 16-wk gestation human fetal lung or from 17-to 18-day fetal rat lung also showed increased total and reduced glutathione when cultured in 95% oxygen, 5% CO, as compared with explants cultured in room air. Type 11 cells isolated from neonatal rats maintained in oxygen for 6 days also showed glutathione levels twice those found in cells isolated from animals in room air. The activity of antioxidant enzymes (glucose-6-phosphate dehydrogenase, glutathione peroxidase, glutathione reductase) was increased in lungs of newborn rats exposed to 100% oxygen either at birth or 2 days of age. Antioxidant enzyme activity of lung explants cultured in 95% oxygen, 5% C02 was also higher than in explants maintained in room air. These results suggest that the increases in glutathione and of antioxidant enzymes in vivo and in viiro are a direct effect of oxygen exposure in lung and that the increase of both glutathione and antioxidant enzyme activity is intrinsic to the lung cell itself. It is likely that increases in glutathione in lung represent an important protective mechanism against oxidant injury. Bronchopulmonary dysplasia is a problem of clinical signifi-. cance in newborns treated with high concentrations of oxygen in the course of therapy for the respiratory distress syndrome. While it is likely that factors such as positive pressure ventilation (1) and patent ductus arteriosis (2) play an important role in. chronic lung disease in newborns, the duration and intensity o i oxygen exposure is thought to be a central etiological feature of bronchapulmonary dysplasia (3). The sequence of injury result-. ing initially in lung injury has been well described (4,5). It has been postulated that highly reactive free radicals of oxygen such as the superoxide anion (02-.) may cause tissue injury by direct peroxidation of unsaturated fatty acids in membranes and alsc~ by oxidation and inactivation of enzymes and other cell constit-, uents essential for cell function. This results in membrane dam-. age with transudation of fluid and formed elements into alveoli and the sequence of injury characterized by fibrosis and chronic clinical impairment.Protective mechanisms against oxidant injury included SOD and the biological systems associated with glutathione or chem-. ical antioxidants such as a-tocopherol. SOD catalyzes the dis-. mutation of the superoxide anion 0 2 -to H202 and 02. The: H202 thus formed can be removed by either catalase or glutathi-. one peroxidase...

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Section: Days Insupporting

confidence: 60%

The Responses of Glutathione and Antioxidant Enzymes to Hyperoxia in Developing Lung

et al. 1985

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“…Assays for palmitate oxidation were carried out 33 4 TIIE JOURNAL OF CELL BIOLOGY • VOLUME 58, 1973 after 3 days in culture . Cells plated at high densities are density inhibited at that time whereas those plated at lower densities are still in logarithmic growth (5) . As is shown in Fig .…”

Section: Resultsmentioning

confidence: 99%

“…Fatty acid oxidation by cultured myocardial cells was measured using methods described previously (5) . Before assay, the growth medium was aspirated from the flasks and the cells were rinsed several times with cold calcium-free Krebs-Ringer phosphate buffer, pH 7 .4, which had been oxygenated before use.…”

Section: Methodsmentioning

confidence: 99%

Interaction of Fatty Acid and Glucose Oxidation by Cultured Heart Cells

Rosenthal

Warshaw

1973

The Journal of Cell Biology

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Chick embryo heart cells in tissue culture actively oxidize [1-14 C]palmitate to 14002 . Fatty acid oxidation by cell monolayers was linear with time and increasing protein concentration . The addition of carnitine to the assay medium resulted in a 30-70% increase in the rate of fatty acid oxidation . The specific activity of palmitic acid oxidation did not change significantly with time in culture and was also the same in rapidly proliferating and density-inhibited cell cultures . Addition of unlabeled glucose to the assay medium resulted in a 50% decrease in 14 CO 2 production from [1-19C]palmitate . Conversely, palmitate had a similar sparing effect on [14 C]glucose oxidation to 19CO2 . Lactate production accounted for most of the glucose depleted from the medium and was not inhibited by the presence of palmitate in the assay. Thus, the sparing action of the fatty acids on glucose oxidation appears to be at the mitochondrial level . The results indicate that although chick heart cells in culture are primarily anaerobic, they can oxidize fatty acid actively .

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“…This suggests that the heart cells switch from lipid to carbohydrate metabolism as they age in vitro (5) . Glucose metabolism via the pentose phosphate pathway has been demonstrated in chick heart embryos (6) and in cultured heart cells (7) . The glycolytic pathway for glucose metabolism is also functional in cultured rat heart cells (5) .…”

Section: Introductionmentioning

confidence: 99%